1. Field of the Invention
The present invention relates to automatic filling machines wherein empty cartons are conveyed along a path while being filled with liquid and then sealed, and more particularly to a valve arrangement for such machines.
2. Description of Related Art
High speed automatic filling machines, such as is disclosed in U.S. Pat. No. 4,448,008, have been used for filling cartons with liquids, such as milk and juices. These filling machines are required to dispense a predetermined quantity of liquid in each carton as it advances through the filling section of the machine.
Such automatic filling machines may be of many different designs, including a double bellows type apparatus, such as those disclosed in U.S. Pat. Nos. 4,402,461 and 4,817,688, or a triple bellows dispensing device, such as those disclosed in U.S. Pat. Nos. 4,840,205 and 4,903,740.
U.S. Pat. Nos. 4,402,461 and 4,817,688 disclose dispensing units having a pair of bellows interconnected by an activator sleeve containing a valve that controls the flow of fluid from the upper bellows to the lower bellows. A discharge valve is mounted at the lower end of the lower bellows. The activator sleeve is mounted for reciprocating movement in an axial direction, and the end of each bellows that is connected with the sleeve moves with it. The opposite ends of the respective bellows are held stationary, so that the axial movement of the body in one direction compresses one of the bellows and expands the other.
The triple bellows dispensing device disclosed in U.S. Pat. No. 4,840,205 includes a valve stem extending axially through at least the lower two bellows. A valve element is mounted at the base of the stem in order to control flow of a liquid through the lowest bellows. The valve element includes radial guides that project radially from the stem and support the stem and the base of the valve element within the nozzle at the base of the lowest bellows.
The triple bellows dispensing device disclosed in U.S. Pat. No. 4,903,740 includes a valve stem extending axially through at least the lowest bellows. A valve element is mounted at the base of the stem in order to control flow of a liquid through the lowest bellows. The valve element includes guide members that extend upwardly from the base of the valve element, parallel to the valve stem. The guide members fit closely within the nozzle opening in order to guide the axial movement of the valve stem through the bellows.
An important function of the radial guides and the guide members of the above-described triple bellows dispensing devices is to separate the liquid flow as the liquid exits the dispensing device in order to allow air to escape from the carton being filled. Unfortunately, the radial guides and the guide members create more turbulence than desired in the liquid as the liquid passes through the valve at the base of the lowest bellows. Thus, although the above-described devices achieve the desirable result of allowing air to escape from the carton while the carton is being filled, the resulting turbulence creates an undesirable amount of foam in the container. In addition, the shape of the base of the valve element causes a small amount of the product to spray, resulting in the seal areas of the carton being filled and adjacent machine surfaces being contaminated with sprayed product.